How to negate exit code status to be used in Kubernetes livenessProbe?

I'll be using the grep command and I would like to do below as a check.

• Return exit value 0, if grep has no hit
• Return exit value 1, if grep has a hit

Since normally, grep will return 0 if there is a hit, can I negate this something like shown below?

!$(cat filet.txt | grep keyword)

CodePudding user response：

Yes you can give it try

example :

    livenessProbe:
  exec:
    command:
    - /bin/bash
    - -c
    - cat filet.txt | grep keyword
  initialDelaySeconds: 10
  periodSeconds: 10

you should checkout if helpful

-v, --invert-match
          Invert the sense of matching, to select non-matching lines.

You can also try -c

echo 'Test' | grep -c T

1

echo 'Test' | grep -c N

0

shell script

#!/bin/sh
if [ $(echo 'Test' | grep -c T) ]; then
  exit 1
else
  exit 0
fi

the easiest way would be writing shell script and managing the exit code for liveness as you want 0 or 1 and based on that liveness will restart the pod.

livenessProbe:
  exec:
    command:
    - /bin/sh
    - -c
    - /home/test/health.sh